Five years after having proton therapy for early- and intermediate-risk prostate cancer, 99 percent of men are living cancer-free and with excellent quality of life, according to a study. Three-quarters of those with high-risk prostate cancer are also disease-free.
The study, published in the International Journal of Radiation Oncology Biology Physics, researchers at the University of Florida Proton Therapy Institute tracked 211 patients who participated in prospective IRB-approved trials. In each track, patients were given proton therapy over an eight-week period, a shorter interval than typical with IMRT, which may last nine to nine-and-a-half weeks.
Physician-reported data show cancer-free survival rates at five years for low-, intermediate-, and high-risk patients are 99 percent, 99 percent and 76 percent, respectively, while overall survival rates are 93 percent, 88 percent and 90 percent.
Moreover, the rate of serious gastrointestinal and urologic complications is low, at 1.4 percent and 5.3 percent respectively for all patients. Patients also reported good outcomes with respect to both urologic and bowel function.
Study: Prostate Cancer Classifier Can Predict Risk Better Than PSA, Gleason Score, and Tumor Stage
A study demonstrated that the Decipher Prostate Cancer Classifier outperformed existing clinical risk factors for predicting biochemical failure and distant metastasis following radiation therapy. The genomic test, developed by GenomeDx Biosciences, is capable of predicting the probability of developing metastatic prostate cancer.
In addition, researchers observed significant improvement in outcomes for patients with high-risk results who received radiation therapy early, compared to after surgery. The data was presented at the 2014 ASCO Genitourinary Symposium.
In the study, 139 patients who had undergone radiation therapy after prostatectomy at Thomas Jefferson University between 1990 and 2009 were analyzed. RNA was extracted from the preserved tissue samples and run on the Decipher test. Patient histories were then analyzed to determine if Decipher was able to stratify patients who could have benefited from earlier radiation therapy.
In patients identified as high-risk, those that got early radiation therapy survived for a median of 8 years without biochemical failure, defined as an increase in PSA post-radiation. This was compared to less than 4 years for patients that got late radiation therapy (p<0.001). At 8 years following radiation therapy, high-risk patients that got early radiation therapy had a 3 percent cumulative incidence of metastasis compared to 23 percent for patients with high-risk results that got late radiation therapy (p<0.001).
Decipher measures 22 genomic biomarkers associated with metastatic cancer to generate a result that indicates the likelihood of metastasis. The result is completely independent of PSA and other existing clinical variables.
